Metal rolls, as utilized in the textile, paper and other industries in manufacturing operations, wet processing or finishing operations, etc., often are required to have a flexible, chemical resistant, rubber-like coating over the entire roll including the ends thereof. The purpose of this rubber-like coating, in addition to giving more resilient surface characteristics, is to prevent corrosion of the metal rolls during such manufacturing uses.
Heretofore, such metal rolls have conventionally been covered by the use of sheet rubber material applied directly to the metal rolls after the surfaces of the metal rolls have been coated with a suitable cement. This technique presented few problems with respect to covering of the circumferential outside longitudinal surfaces of the generally cylindrical metal rolls. However, problems were presented with respect to covering of the ends of these metal rolls from which there normally extends small stub shafts for supporting of the rolls in the machinery in which they are utilized.
Covering of these ends of the metal rolls has, heretofore, normally been performed by plying up sheets of calendered sheet rubber stock, cutting these sheets of rubber stock into discs of the diameter of the ends of the metal rolls, and finally applying these cut discs of sheet rubber stock to cemented ends of the metal rolls. In order to make sure that the entire ends of the metal rolls are covered by these cut discs of sheet rubber stock, it was often necessary to make a diametrical cut in these discs of sheet rubber stock in order to attempt to apply these discs around the extending shafts from the ends of the metal rolls. This prior practice was time consuming and often resulted in uneven and inadequately covered ends on the metal rolls.
The sheet rubber stock material utilized in these prior conventional practices was normally a compound of conventional solid natural or synthetic elastomeric material or rubber, which required considerable energy for their formation into sheets or strips and the sheets or strips had to be maintained under high pressure during their vulcanization to prevent delamination. These sheet rubber stock materials normally had a molecular weight range from about 200,000 to 600,000 and required from 200 to 10,000 psi to form it before vulcanization.
Although other techniques of covering metal rolls including the ends thereof have been proposed, and other rubber or elastomeric compositions for use in covering the ends of metal rolls have been proposed, none of these have been found satisfactory for overcoming the problems set forth above and produced additional problems which resulted in unsatisfactory commercial processes and compositions for covering the ends of rolls or unsatisfactory covered rolls. Examples of such prior roll covering processes and rubber-like compositions may be found in the following patents which have been considered at the time of filing of the present application:
______________________________________ U.S. Pat. No. Inventor Issue Date ______________________________________ 1,736,911 Gray November, 1929 1,943,275 Lerch January, 1934 2,333,800 Lewis et al November, 1943 2,582,795 Prentiss et al January, 1952 2,950,990 Johnson August, 1960 3,046,178 Tupper July, 1962 3,313,764 Iino April, 1967 3,331,907 Salzinger July, 1967 3,354,243 Dodge November, 1967 3,677,856 MacCallum et al July, 1972 3,726,736 Wolfenden April, 1973 ______________________________________